Characterization of a pangolin SARS-CoV-2-related virus isolate that uses the human ACE2 receptor.

Various SARS-CoV-2-related coronaviruses have been increasingly identified in pangolins, showing a potential threat to humans. Here we report the infectivity and pathogenicity of the SARS-CoV-2-related virus, PCoV-GX/P2V, which was isolated from a Malayan pangolin (Manis javanica). PCoV-GX/P2V could grow in human hepatoma, colorectal adenocarcinoma cells, and human primary nasal epithelial cells. It replicated more efficiently in cells expressing human angiotensin-converting enzyme 2 (hACE2) as SARS-CoV-2 did. After intranasal inoculation to the hACE2-transgenic mice, PCoV-GX/P2V not only replicated in nasal turbinate and lungs, but also caused interstitial pneumonia, characterized by infiltration of mixed inflammatory cells and multifocal alveolar hemorrhage. Existing population immunity established by SARS-CoV-2 infection and vaccination may not protect people from PCoV-GX/P2V infection. These findings further verify the hACE2 utility of PCoV-GX/P2V by in vivo experiments using authentic viruses and highlight the importance for intensive surveillance to prevent possible cross-species transmission.

Metavirome of 31 tick species provides a compendium of 1,801 RNA virus genomes.

The increasing prevalence and expanding distribution of tick-borne viruses globally have raised health concerns, but the full repertoire of the tick virome has not been assessed. We sequenced the meta-transcriptomes of 31 different tick species in the Ixodidae and Argasidae families from across mainland China, and identified 724 RNA viruses with distinctive virome compositions among genera. A total of 1,801 assembled and complete or nearly complete viral genomes revealed an extensive diversity of genome architectures of tick-associated viruses, highlighting ticks as a reservoir of RNA viruses. We examined the phylogenies of different virus families to investigate virome evolution and found that the most diverse tick-associated viruses are positive-strand RNA virus families that demonstrate more ancient divergence than other arboviruses. Tick-specific viruses are often associated with only a few tick species, whereas virus clades that can infect vertebrates are found in a wider range of tick species. We hypothesize that tick viruses can exhibit both 'specialist' and 'generalist' evolutionary trends. We hope that our virome dataset will enable much-needed research on vertebrate-pathogenic tick-associated viruses.

A Chess and Card Room-Induced COVID-19 Outbreak and Its Agent-Based Simulation in Yangzhou, China.

Objective: To evaluate epidemiological characteristics of the COVID-19 outbreak that resurged in Yangzhou and to simulate the impact of different control measures at different regional scales. Methods: We collected personal information from 570 laboratory-confirmed cases in Yangzhou from 28 July to 26 August 2021, and built a modified susceptible-exposed-infected-removed (SEIR) model and an agent-based model. Results: The SEIR model showed that for passengers from medium-high risk areas, pre-travel nucleic acid testing within 3 days could limit the total number of infected people in Yangzhou to 50; among elderly persons, a 60% increase in vaccination rates could reduce the estimated infections by 253. The agent-based model showed that when the population density of the chess and card room dropped by 40%, the number of infected people would decrease by 54 within 7 days. A ventilation increase in the chess and card room from 25 to 50% could reduce the total number of infections by 33 within 7 days; increasing the ventilation from 25 to 75% could reduce the total number of infections by 63 within 7 days. Conclusions: The SEIR model and agent-based model were used to simulate the impact of different control measures at different regional scales successfully. It is possible to provide references for epidemic prevention and control work.

Generation of the salicylic acid deficient Arabidopsis via a synthetic salicylic acid hydroxylase expression cassette.

BACKGROUND: Salicylic acid (SA) is one of the plant hormones, which plays crucial roles in signaling transduction in plant growth, disease resistance, and leaf senescence. Arabidopsis (Arabidopsis thaliana) SA 3-hydroxylase (S3H) and 5-hydroxylase (S5H) are key enzymes which maintain SA homeostasis by catalyzing SA to 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA, respectively. RESULTS: SA deficient transgenic Arabidopsis lines were generated by introducing two binary vectors S5Hpro::EGFP-S3H and 35Spro::EGFP-S3H respectively, in which the expression of S3H is under the control of the S5H promoter or CaMV 35S promoter. Compared with the constitutive expression of S3H gene under the control of 35S promoter, the S3H gene under the native S5H promoter is activated by endogenous SA and results in a dynamic control of SA catabolism in a feedback mode. The SA accumulation, growth, leaf senescence, and pathogen resistance of the S5Hpro::GFP-S3H transgenic plants were investigated in parallel with NahG transgenic plants. The SA levels in the S5Hpro::EGFP-S3H transgenic plants were similar to or slightly lower than those of NahG transgenic Arabidopsis and resulted in SA deficient phenotypes. The low-SA trait of the S5Hpro::EGFP-S3H transgenic lines was inherited stably in the later generations. CONCLUSIONS: Compared with NahG transgenic lines producing by-product catechol, S5Hpro::EGFP-S3H transgenic lines reduce SA levels by converting SA to a native product 2,3-DHBA for catabolism. Together, we provide new SA-deficient germplasms for the investigations of SA signaling in plant development, leaf senescence, and disease resistance.

Relationships between sarcopenia, depressive symptoms, and mild cognitive impairment in Chinese community-dwelling older adults.

BACKGROUND: Mild cognitive impairment (MCI) represents an intermediate state between normal cognitive aging and dementia. We aimed to investigate the association and mediation pathways of sarcopenia, including its individual components (muscle mass, muscle strength, and physical performance), and depressive symptoms with MCI in the older adults. METHODS: This study consisting of 1394 community-dwelling Chinese older adults aged 60 years and older in Tianjin and Shanghai, China. Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) criteria. Depressive symptoms were evaluated by the 30-item Geriatric Depression Scale (GDS). Cognitive function was assessed by Mini-Mental State Examination (MMSE), the Chinese version of the Dementia Rating Scale (CDRS) was used to apply the diagnostic of non-dementia, and instrument activities of daily living (IADL) were used to evaluate daily living activities. Logistic regression and mediation analyses fully adjusted for all potential confounding factors were conducted. RESULTS: Sarcopenia, handgrip strength, gait speed, and depressive symptoms were associated with MCI. Furthermore, depressive symptoms significantly mediated the association of sarcopenia, handgrip strength, and gait speed with cognitive function. The relationship of depressive symptoms and cognition were also mediated by sarcopenia, handgrip strength, and gait speed. LIMITATIONS: This is a cross-sectional study. CONCLUSIONS: Our findings suggest that sarcopenia may contribute substantially to the development of MCI in the older adults via depressive symptoms, although the reverse may also be true. These findings may help guide clinicians to better diagnose and manage MCI in the context of concomitant sarcopenia and depressive symptoms.

Muscle mass rather than muscle strength or physical performance is associated with metabolic syndrome in community-dwelling older Chinese adults.

OBJECTIVE: The purpose of this study was to examine whether muscle mass, muscle strength, and physical performance were associated with metabolic syndrome (MetS) in community-dwelling older Chinese adults. METHODS: The study comprised of 1413 community-dwelling Chinese participants (577 men; mean ± standard deviation age: 71.3 ± 5.9) recruited from Tianjin and Shanghai, China who were invited to participate in a comprehensive geriatric assessment. The International Diabetes Federation metabolic syndrome guidelines were used to define MetS, including high waist circumference, elevated blood pressure, elevated fasting blood glucose, elevated triglycerides, and reduced HDL cholesterol. Muscle mass was measured by appendicular skeletal muscle mass/weight (ASM/weight), and ASM was measured by BIA. Muscle strength was measured using grip strength. Physical performance was represented by walking speed and the time up and go test (TUGT). RESULTS: The overall prevalence of MetS was 46.8% (34.1% in males and 55.5% in females). In the final logistic regression model, there was a significant, graded inverse association between muscle mass and MetS (p for trend = 0.014). Muscle strength and physical performance, including walking speed and TUGT, were not associated with overall MetS. In the components of MetS, muscle mass and grip strength were significantly inversely associated with high waist circumference and elevated blood pressure (p < 0.05), while physical performance was not associated with components of MetS. CONCLUSIONS: Compared with muscle strength and muscle function, muscle mass was inversely associated with MetS in a community-dwelling elderly Chinese population. Among muscle mass、muscle strength and physical performance, muscle mass appears to have the strongest association with MetS in the elderly.

Prediction of the Auto-Ignition Temperatures of Binary Miscible Liquid Mixtures from Molecular Structures.

A quantitative structure-property relationship (QSPR) study is performed to predict the auto-ignition temperatures (AITs) of binary liquid mixtures based on their molecular structures. The Simplex Representation of Molecular Structure (SiRMS) methodology was employed to describe the structure characteristics of a series of 132 binary miscible liquid mixtures. The most rigorous "compounds out" strategy was employed to divide the dataset into the training set and test set. The genetic algorithm (GA) combined with multiple linear regression (MLR) was used to select the best subset of SiRMS descriptors, which significantly contributes to the AITs of binary liquid mixtures. The result is a multilinear model with six parameters. Various strategies were employed to validate the developed model, and the results showed that the model has satisfactory robustness and predictivity. Furthermore, the applicability domain (AD) of the model was defined. The developed model could be considered as a new way to reliably predict the AITs of existing or new binary miscible liquid mixtures, belonging to its AD.